thicken up

B1 neutral separable both

In simple words

To get thicker — like when a sauce gets less watery as it cooks.

Literal meaning: To increase in physical thickness.

Meanings

1 B1 neutral

common

To become or make a liquid or mixture thicker in consistency.

"Add a spoonful of cornflour to help the gravy thicken up."

Grammar: separable

2 B2 neutral

uncommon

To become denser or more substantial in volume (hair, fog, crowd, etc.).

"The morning fog began to thicken up as they drove towards the coast."

Usage notes

Most common in cooking contexts. 'Up' emphasises completion of the process. Can also be used for hair, crowds, or fog becoming denser.

sauce soup gravy hair fog mixture

Base

thicken up

I/you/we/they

3rd person

thickens up

he/she/it

Past simple

thickened up

yesterday

Past participle

thickened up

have + pp

-ing form

thickening up

continuous

Try:

Video examples are being collected. Check back soon.

thicken reduce set congeal condense

Want to master this phrasal verb?